Hydraulic circuit



p 9 s. A. WAHLMARK 7, 40-

HYDRAULIC CIRCUIT Filed May 15, 1937 2 Sheets-Sheet 1 Sept. 30, 1941. WAHLMARK 2,257,140

HYDRAULIC 'cxncurr Filedlay 15, 1937 2 Sheets-Sheet 2 Patented Sept. 30, 1941 i Gunnar A. Wahlmark, Rockford, Ill.

Application May 15, 1937, Serial No. 142,887

9 Claims. '(c'l. 60-52) The invention relates to a-hydraulic circuit and has as a general vobject to provide a novel and improved circuit for supplying operating fluid to a hydraulic motor at selectively different rates for actuating a member driven by the motor at different speeds, in. opposite directions and under different loads.

A more particular object of the invention to provide a novel and improved hydraulic circuit I inafter be described in a preferred embodiment,

particularly adapted for supp y ng operating fluid to a reversible hydraulic motor at relatively 1 different rates and directions of flow for reciprocating a tool or work support of a machine tool at diflerent speeds and under diiierent loads.

Another object of the invention is to provide a new and improved hydraulic circuit for a machine tool which is unusually flexible in its adjustments and operation so as to make readily obtainable a large variety of cycles of operation of the machine tool. p

Yet another object is to perfect a hydraulic circuit operable to drive a member in opposite directions and at different rates of speed in which an individually operable remote control valve is provided for controlling each the starting and stopping of the member, the particular rate of travel of the member, and the reversal of the member. V

A further object is to perfect a hydraulic circuit for driving a member through various cycles of operation, including starting and stopping of the member, movement in a forward or return direction, and feed or traverse rate of movement, which includes hydraulically actuable main governing valve mechanism controlling the direccircuit, and a plurality of independently operable remote control valves, each being electrically actuated and inde den associated hydraulipen fly 40 is in engagement'with the work-and performs cally'with the governing mechanism for controlling one of the steps in the cycle of operation of the member.

Still a further object is to provide a hydraulic circuit of the character described in which dwell of the member prior to reversal may "be obtained without the addition of valv means not required for a cycle of operatim omitting dwell.

Yet a further object is to perfect a hydraulic circuit capable of driving a member at three automatically obtained feed rates of movement.

Other objects and advantages will become apparent from the following detailed description taken 'in connection with the accompanylm drawings, in which:

Fig.1 is a piping diagram of a hydraulic circuit embodying the features of the invention."

Fig. 2 is a schematic diagram of the hydraulic circuit shown in Fig. 1. a

Fig. 3 is a fragmentary diagrammatic view of aportion of the circuit modified to obtain a dwell.

Though the hydraulic circuit is susceptible of various modifications and alternative constructions, it is shown in the drawings and will herebut it is not intended that the invention is to be limited thereby to the specific construction disclosed, but it'is' intended to cover all modiilca tions and alternative constructions falling within git the spirit and scope of the inventionas defined by the appended claims.

While a hydraulic circuit embodying the teatures of the invention might be employed in a 'variety of devices and througha hydraulic motor actuate a member at different speeds and through difierent cycles, the hydraulic circuit is for purposes of disclosure. herein shown and will hereinafter be described as particularly adapted for drivinga table or support of a machinetool.

Such a table or support is here represented at 9 (Fig. 2) and is adapted to be. driven to the left' from its normal or stop position to the limit of its movement in that direction, and is then reversed andreturned to its normal position. In

such reciprocation, the table is normally driven at diiierent'speeds. One such speed is a high speed which is imparted to the table-while the tool and the work are out of engagement and is commonly called "rapid traverse. This traverse.

rate is. employed in either forward or returnlion and volume of flow of operating fluid in the;

movement of the table, while the work and the tool are being brought together or while they are being? separated." Another such speed is a mhstantially lower speed during whichthe tool its cutting operation. This'speed must be maintained with a high degree of andf uniformity as compared with rapid traverse and is commonly known as "feed." This "feed" rate of movement may be varied and provision is here made for obtaining three feed speeds.

The table may also be arrested temporarilyat somepoint otherthanits normal stopposition, usually at the nd of its forward movement, and

this temporary arrest-isknown as dwell." "Provlded the circuit is flexible enough, movement 7 and comprises pumping mechanism (see Fig. 2)

composed of a large output constant displacement pump I3, commonly known as a traverse pump, and a low output variable displacement pump l4, commonly known as a feed'pump,

'and governing mechanism composed of a plul5 rality of .valve means directly associated with,

. the pumping mechanism for controlling the fluid discharge from the device. Pump I4 is of unique construction and is associated with the traverse pump and th motor in ,a unique manner so that all fluid flowing to the motor passes through the- .pump I4 and so that the pump l4 functions or acts in a variety of ways'upon different quantities of fluid supplied by the traverse pump and thus determines the quantity of 'fluid supplied to the motor, though both pumps continue to operate. More particularly, under one condition the pump I 4 functions to discharge no fluid whatsoever with the result that the motor remains stationary, while under another condition, the pump H functions to meter and to boost the pressure of a portion of the fluid supplied by the traverse pump thus to drive the motor at a feed rate, and, while under yet a different condition, the pump I4 functions to pass all of the fluid supplied by the traverse pump without acting thereon with the result that the motor is driven at a "traverse rate.

Ofthe plurality of valve means constituting the governing mechanism, a valve means generally designated l5 governs the volume of fluid discharge from the device and includes valves governing the conditions determining the manner in which the pump l4 functions and a valve controlling the displacement of the pump l4. Other valve means generally designated l6 governs the direction of fluid discharge from the device H and consists of a single valve, while a third valve means generally designated ll limits the pressureof the discharge and consists of two valves,

one-in the nature of a high pressure relief valve .and the other in the nature of a low pressure limit valve or circuit locking valve. The governing mechanism and the pumping mechanism,

as previously stated, are formed as a unitary device housed in a casing l2 as shown in Fig; 1,

which'casingis diagrammatically represented in Fig. 2 by the dot-dash line enclosing the pumping and governing mechanisms. Such embodiment unitary structure is more particularly disclosed and claimed in my application Serial No. 141,327

filed May 7,- 1937' (issued Sept. 10; 1940, a p t t No. 2,214,390). v r

. The remote control means is composed of a plurality of independently operable valve means, each controlling'or effecting a predetermined portion of the cycle of operation of the table. These valve means are associated with. the governing mechanism of the device I I and are independently 70.

controlled to obtain. a desired cycle of operation.

The pressure generating and control device ll disclosed hereinis the same as that disclosed in my. Patent No, 2,214,390 .and will thus be described briefly, reference being made 'to my patent just referred tofor a more complete disclosure of the precise formation and location, in

a unitary structure, of the pumping mechanism, the governing mechanism and the passages and ducts interconnecting the same.

.tinuously rotated during the operation of the machine tool and functions in well known manner to draw fluid, preferably oil, into the pump from a tank or reservoir 20 through an intake pipe 2|, an intake port 22 formed in the casing l2 and a port 23 of the pump and to discharge the fluid through a port 24 into a passage 25 formed within the casing I2. 1

When the tool is in engagement with the work, that is, during the feed movement of the table, a slow uniform movement of the table is re'quired andnecessitates the supply to the motor 10 of a sm ll quantity of fluid at "an accurately metered 'rate. The pump l4 for supplying such an accurately metered quantity of fluid herein takes the form of a variable displacement piston pump of novel construction, more particularly described and claimed in my copending application Serial No. 60,646, flled January 24,1936, now abandoned,

and my Patent No. 2,214,390. This pump comprises a plurality of annularly disposed parallel cylinders 30, each having a piston 3! reciprocable therein which in all positions has one endprojecting' from the cylinder. The pistons 3| are actuated by a wobble plate 32 swiveled on a ball 33 and having anarm 34 projecting centrally of the cylinders into asocket 35 formedin the end of a drive shaft 36 oblique to the axis thereof. The pistons 3| merely abut thev wobble plate 32 and are not positively connected thereto so that the wobble plate is capable of imparting an exhaust stroke only to the pistons but is unable to impart a return or intake stroke thereto, thus making the pump non-self-priming. Each cylinder 30 has an intake port and an exhaust port with the intake portcontrolled by a check valve 31 functioning to permit flow of fluid into the cylinder but preventing return flow out of the cylinder, and with the exhaust port controlled by a check valve 38 which functions to permit discharge from the cylinder but to prevent return of governing and pumping mechanisms in a single 60 flow into the cylinder. All of. the intake ports open into a charging passage 39 communicating with the passage 25,-and all of the exhaust ports open-to asupply passage lflo Shaft 36 also drives The displacement of the pump-I 4 maybe varied by changing the stroke of the pistons 3| and this is accomplished by relative axial adjustment of the wobble plate 32 and the shaft 36. Such relative adjustment varies the extent to which, the

arm 34' is received in the oblique socket 35 thereis accomplished by movement 'of the wobble plate 32, and to that end the ball 33 upon which the wobbleeplate is 'swiveled is formed on the end of a piston ll slidable inthe inner end of the bore Movement of the table at a high speed or traverse ratere- .easingl'z of a cylinder 42. The piston may be manually set at a predetermined fixed displacement of the pump by means of cam rings 43 and 44 rotatable knobs 41 and 48 (see Fig. 1) disposed outwardly of the casing |2 for convenient adjustment of the displacement of the pump.

The displacement of the pump |4 may also be varied automatically by hydraulic means. Herein this means is capable of adjusting the pump M to any one of three displacements and comprises in addition to the piston 4| and the cylinder 42 a second piston 49 reciprocable in the outer end or the bore of the'cylinder, 42- and adapted to abut the outer end of the piston- 4| to shiit'the same. The piston 49 is limited in its inward movement by anadjusting rod 56 having a lost motion connection at its inner end with the piston 49 and fixed at its outerv end in a cap 5| adjustably threaded upon the end ofv the cylinder 42. Opening to the outer end of the bore in the cylinder 42 is a port 52 threaded iorthe reception of a conduit, and opening to the bore intermediate the pistons 4| and 49 is a port 53 also threaded for the reception of a conduit.. when the displacement of the pump I4 is to be varied automatically, the rings 43 and 44 are employed Theately adjacent and on sage 25, the bore 55 is formed with an annular groove 56 and an annular groovev 51. 'Bothgrooves 56 and 51- jcom'municate with a large pas- 5 sage .56 terminating in a return port 59 formed the piston 4|, by

in the casing |2 opposite "the intake-port 22 and threaded tor the reception of a return pipe 60 leading to the reservoir 26.

Flow of fluid fromthe passage 25 to the groove i0 56 is controlled by a valve 6| in the form of a hollow piston which functions as a start and stop 'valve as will later become more apparent. The valve 6| has two positions, namely, an open position as shown in Fig. 2 in which flow is permittedfrom the passage to the groove 56 and a closed position determined by abutment of the valve with a plug 62 in which the head or closed end of the valve projects into the opening between the passage 25 and the groove 56 to prevent flow therethrough. The valve is normally urged to its closed position by'means of 'a light compression spring 63 which is disposed within the valve with one end abutting the closed end of the valve and the other end abutting a plug 64 having a fluid-tight fit in the bore 55. Interj mediate the groove 56 and' the plug 64, the bore 55 is formed with a second ,smaller annular groove 65 and immediately adjacent the plug 64 a port 66 opens to the bore. vBy means of a passage 61, port 66 is connected to a first exter-' nal control fluid port I threaded for the reception of a conduit, while groove 65 is connected by a duct 68 to the supply'passage 46. 'Port' 66 is always open and is not controlled by the valve 6|,,but groove 65 is controlled by valve 6| and merely to limit the movement of the piston and thus predetermine the maximum and mini-' correspondingly rotated'to permit movement of mum displacement to which the pump may be shifted automatically. The rings 43 and 44 are the piston 4| and are positioned to constitute stops against which the rod 45 abuts at the predetermined time in either the inward or the outward movement of the piston4l. Ring 43 deter- 45 mines the maximum desplacenient oi the pump and the piston 4| is normally urged to the limit permitted by the ring 43 by the reaction of the fluid in the cylinders 35 on the pistons 3|, while ring 44 determines the limit of inward movement of the piston 4| when fluid pressure'is applied through the port 53 and thus determines. the minimum displacement of the pump. The cap 5| and rod 50 controlling theinward movement to limit the shift of the piston 45, and thecorrespending shift of the piston-4|, when fluid pressure is applied through the port 52, to a position of the piston 4| intermediate that determined by o the spring 63, having one end abutting the closed the rings 43 and 44 in order to obtain an'intermediate displacement. The manner in which the fluid is supplied to the ports 52 and 53 will be described more fully hereinafter.

Having described for controlling mechanism and the volume, direction and presnow be described. As previously stated, the volume of discharge is controlled by valve means generally designated I5 and this means is composed in a v and intersecting the passage 25 to which the gear pump l.3' discharges. Immedithe pumps constituting the.

pumping mechanism, the governing mechanism the functioning or the pumping sure of discharge of fluid from the device II will posed of three independently operable valves dis- I bore 55 extending transversely'oi-the 7 the manner in which the pump l4 functions. I

to that end'the'mvalve is formed with an external annular groove 69 which is of such width and is so positioned on the valve as to eflect communication between the groove and the to close the groove 65 when the valve is in closed position. Dust 66 provides an escape for slippage fluid when thedevice H is not discharging fluid.

Communication betweenthe passage 25 and the groove 51 likewise is controlled by-a valve 10 v in the form of a hollow piston, similar to the valve 6|,,which functions as arate change or charging valve. This valve also has two posihead end of the valve projects into the opening betweenthe passage 25 and the groove 51 to preoi the piston 49 are proportioned and adjusted 55 Shown n a an a Op P i n hifted for head end of the valve 19 and the other end abutting a cap 12 closing one end of the bore 55.

Opening to the bore adjacent the cap 12 is a port 12'. Y

Each of the valves 6| and I0 is formed at its closed or head end with a small opening 13. to permit'bleeding of fluid from passage 25.to the interior of the'valve. This opening preferably is covered. by a screen (not shown) to prevent clo ging of the opening by foreign material.

As previously stated, the valve 6| functions as a start and stop valve,'while the valve 16 Iunc-.

tions as a rate change or charging valve, both valves governing the conditions" which determine opposite sides of the pasgroove 56 when the valve is in open position but tions, namely, a closed position in which the The strength of the spring 68 controlling the valve 8| is such that when the fluid bleeding through the opening 13 is free to return to the reservoir 20 the valve normally maintains a low pressure in the passage 25, which is insuflicient to open the intake check valves 31 of the variable displacement pump I4 and impart a return stroke to the pistons 3| thereof. Thus, when the valve is controlled by the spring 83 only, no discharge from the device II takes place for the valve 8| is opened by the low pressure of the fluid in the passage 25, thereby permitting escape of the fluid a pump- I4 rendering the same operative to discharge fluid from the device in metered quantities, any excess of fluid supplied by the traverse pump being returned to the reservoir through passage .58 and pipe 80. Either or both of the valves BI and 10 may be positively held in closed position by blocking the escape of the hydraulic fluid bleeding into the valves through the openings 13 formed in the end thereof. Such blocking causes the pressure; on oppositesides of the valve to be equalized thereby rendering the spring capable of closing the ,valve. When valve BI is positively held closed, discharge takes place from the device II as determined by the valve 10'. If

valve 10 is then closed only-by spring 1|, the valve functions to charge the pump I4 and the volume of discharge fromthe device is low as determined by the displacement of the feed pump I4, but if valve 10 is positively closed, the volume is large as determined bythe displacement of the traverse pump I3. Valve 10 thus determines whether the table is driven at a feed or a traverse rate of movement; and unless valve 10 is positively held closed, positive closure of the valve- 6| to initiate operation will start the table at a fast feed rate.

At its right end, the bore 55 is closed by a cap 15 having a third external control fluid port 8 opening therethrough and threaded for the reception of a conduit. An annular groove 16 opens.

to the bore 55 and communicates with a duct 11 which terminates in an external port 4 threaded for the reception of an external conduit #4 leading to the port 53 of the means for varying the displacement of pump I4. The end of the bore opposite the cap 15 is adapted to be connected to'the reservoir to permit the exhaust of fluid returned through duct 11 and to that end is here shown formed with a port 18 connected by a duct '18 to the passage 58. .Also opening to the bore 55 is a port 80 connected 'by a branch 88' of duct 68 to passage 40 for supplying high pressure fluid to the bore. v

. Reciprocable in the right end of'the bore 55 is a valve 85, in the form of a hollow piston, controlling the supply of fluid to the port 53 of the means for varying the displacement of the variabledelivery pump I8. The valve is yieldably urged to the right to the position shown in Fig. 2,

by a compression spring 88 received in the valve and acting between the closed end of the valve and the plug 54. The valve is formed intermediate its ends with an annular external groove 81 and with radial apertures 88. These are so passage 18 and thence to the reservoir of any fluid returned through the duct 11. However. when fluid pressure is applied to the right end of the valve through the port 3, the valve is shifted to the left and the groove 81 serves to' pp y connect the port 80 with the groove 15 to high pressure fluid to the port 53.

.To accommodate the valve means, generally designated I8, controlling the direction of fluid discharge from the unitary device II, the casing I 2 is formed near the top with a transversely extending bore 90, closed at one end by a cap 8I and at the other end by a cap 82. Cap 8| has formed therein a fifth external control fluid port 5 threaded for the reception of a conduit. Substantially midway between its ends, the bore 80 has opening thereinto five annular and axially' spaced grooves 88, 84, 85, 86, and 81. The intermediate one of these grooves 85 communicates by means of a large passage v88 with the supply passage 40. The grooves 88 and 86 on opposite sides of the groove communicate respectively with large external ports 88 and "I00 threaded for the reception of conduits leading to the hydraulic motor to'be supplied with fluid. End groove 83 is connected by a passage WI and a passage I02 to the end groove 81 and to the valve means controlling the return fluid, as will pres-y ently be described. Intermediate the groove 83 and the cap 8|, the bore is formed with a narrow holding groove I03 which is connected by a duct I04 with the passage 25 to which the gear pump I3 discharges. Intermediate the groove 91 and the cap 82, the bore 80 is formed with a narrow annular groove I05 which groove is connected by a passage-12" with the port 12' of the bore 55. Adjacent the groove I05 is anexternal port 2' threaded forthe reception of a conduit.

Reciprocable in the bore 80 to control the various grooves, is a spool valve I08 provided with wide end lands I01 and I01 and two intermediate lands I01, all spaced axially a distance embracing two grooves in the bore. Extending axially of the valve is a passage I08 communicating at one end by means of radial ports with a leakage groove I08'- formed in the land I01 and opening at the other end into a recess I08" formed in the end of the valve. The valve has two'positions, namely, a forward position, shown in Fig. 2, to which it is urged by a compression spring I08 received at one end within the recess I08", and a return position to which it is shifted by the application of fluid pressure through the port 5. It will be seen that in the forward position shown, grooves 84 and are bridged so that the discharge from the variable delivery pump I4 is directed to the port 88, while grooves 86 and 81 are also bridged so that the return fluid entering through port I00 may be directed to the return fluid controlling valve means through passage I02. In this position,'groove I05 and port 2' are bridged by a groove I08 formed in the land I01. When shifted to the left to return position, groove 851s then connected to groove 88 while groove 84 is connected to groove 83 to reverse the direction of discharge and re-.

.turn of fluid from and to the ports and I00.

In "return positiomgroove I05is blocked while groove I08 is now uncovered to permit the supply of fluid through duct I08 to hold valve I05 in shifted position. v

To accommodate the remaining valve means I I, the casing I2 is formed with a transversely extending bore H disposed intermediate the bore 55' and the bore 90. The bore H0 has opening thereinto 'an annular groove III into which opens passage I02 communicating with the end grooves 83 and 91 of the reversing valve means. An annular groove H2 to the right of the groove III communicates by means of a passage H2 with the passage. 58 and return port 59, and 1t) an annular groove H4 at the extreme right end of the bore also communicatesby means of a. passage H4 with the passage 53. Also dpening to the bore H0.intermediate the grooves H2 and passage H2" and by a duct H3". with a port H4 is a groove H0 communicating with the sup- H5 opening to the bore 00 adjacent thecap 32.

Thus, any fluid which happens to be in the'left end of the bore 90 may be discharged to the reservoir when'the valve I 06 is shifted.

Interposed ,between the grooves III and H2 and suitably Ported to communicate with the 5.

groove III is a centrally apertured member II'I forming a seat for a valve I I8 controlling the return fluid. The valve I I3 isslidably supported in a tubular member us received in the left end of the bore H0 and retained therein by means-o1 3 a hollow cap I20 threaded into the end of the bore. Urging the valve H8 t o seated position is a compression spring I2I which at one end bears against a flanged washer on the stem of the valve H8 and at the other end bears against a washer swiveled on the'end of an adjusting screw I22. The member I I9 has radial ports registering with the groove H3 to permit discharge of any fluid,

. leaking along the valve H0.

It will be apparent that the valve H8'is.not

responsive to the pressure of the return fluid in the passage I02, and to actuate the valv H0, means is provided which is responsive to the 'sup-' ply fluid pressure only. Accordingly, there is'received in the right end of the bore H0 a tubular 5 member I25 retained in the bore by means of a hollow cap I26 threaded into the bore. 'Themember I25 is suitably apertured to provide communication betweerr the bore I I4 and the interior of the member and is also apertured to provide communication between'the interior of the memher and the groove H6 communicating with the fluid supply passage 40. Interposed between the member H1 and the member I25 is a piston I21 having a point engaging the end of the valve H8 pressure within the conduit. Valve BI is thus for the purpose of shifting the valve upon actua- -tion of the piston I21. To subject the piston I21 forthe purpose of avoiding injury to the system. It constitutes a high pressure limit.

The remote control means comprises a plurality of individual and independently operable valve means connected by means of conduits to the external ports of the device II so that each valve means controls one of the steps or stages of operattion in the cycle'of movement of the table 3.- With this arrangement, an unusually, flexible control is obtained, for the duration of a stage in the cycle is determined by'theflength of actuation ofthe valve means controlling that stage, and the presence or absence of a stage in the cycle likewise is controlled by the operation or non-operation of the particular valve means controlling such a stage;

Herein five such valve means are shown and are respectively designated SV, RV, TV, FjV and F2V. These valve means are generally similar, each having a casing I40 with a longitudinal bore formed therein and a valve I4I slidable in the bore. The valve I has a normal" position and a shifted position to which it is moved by suitable means in opposition to the spring I42. The valve means differ in the porting and groovingv formed in the bore and the valve proper, with a the exception that each casing is formed at its lower end with an exhaust port I40 connected to a common return conduit #9 leading to the reservoir 20.

The casing of the valve means SV is formed with a narrow annular groove I43 and a narrow annular groove I44 spaced axially from the groove I43 and both opening to the bore. The valve of the valve means SV is formed with two external annular grooves which in the normal position of the valve register with the grooves I43 and I44 of the bore and whichcommunicate by means of radial ports with an axial passage opening through the lower end of-the valve to the bore in the casing, In its shifted. positio the valve blocks the grooves I43 and I44 to prevent any discharge from the grooves to the bore in the casing. Since the valve means SV is intended to. control vthe starting and stopping of the table, the groove I43 thereof is connected by a conduit #I to the external portI of the device II which port, as previously stated, is associatedwith the start and stop. valve BI to control the initiation and arrest of discharge of fluid to the motor I0. It will be apparent that with the valve of the start and stopvalve means SV in fnorma position the conduit #I is open to the reservoir and thus prevents the building up of held closed only by thespring -63 and no dis- Preferably, a gscreen H0 and piston I21 being responsive only to 65 he supplyipressure function as a circuit locking means and as a low pressure limit means. To the rightvof the apertures registering withjthe groove I IS; the member I25 is formed to prqyide a seat I4I in shifted position however, the conduit." .#I will be blocked and thus initiate discharge of fluid to the motor I0.

The casing of the valve means TV is formed with bitt a single annular groove I45 opening to the bore" therein, while the ,valve MI is also formed with but a single annular groove which in the normal position of the valve registers with the groove I45 and which communicates by jmeans of radial ports with an axial passage for a disk valve I29 which serves as a relief valve.

The valve is urgedto seated position by means of a heavy, compression spring I30 which abuts against .a washer resting on'an adjusting screw I3I threaded into the cap I20. This valve is adjusted toopen only at extremely high opening through the lower end of the valve to the bore in the casing. Since this valve means is in- :tended to determine traverse operation of the motor I0,-the groove I45 of the casing i conpressures' described, in the fo nected by anexternal conduit #2 to the external port 2' of the device II. This port, as previously ard position of the revers ving valve I06 is in communication with the interior of the charging or rate change valve I through the duct 12. From the foregoing, it will be apparent that when the valve of the traverse valve means TV is in normal position the conduit #2 is in communication with the reser-' voir 20 and thus there can be no building up of pressure of the fluid bleeding into the valve I0 and thus the valve I0 cannot be positively held in closed position. However, when the valve I of the traverse valve means is-shifted, conduit #2 sure within the valve I0, positively closing the same and causing the entire discharge of. the

traverse pump to be supplied to the motor I0 to eflect a traverse rate of movement.

, The casing of the valve means-RV is formed with an annular groove I46 and an annular groove I 41 opening tothe bore, while the valve proper is formed with a wide annular groove I40. In the normal position of the valve proper the groove I40 registers with the groove I", while the groove I46 is blocked,,while in shifted'position of the valve, groove I48.bridges the grooves I46 and I41 to effect communication therebe-' is connected by means of an external conduit #6 to the external port 6 which leads to the passage 25 to which the traverse pump I3 discharges. Conduit #6 serves as a control fluid supply conduit. From the foregoing it will be seen that when the valve of the reversingvalve means RV is in normal position, the conduit #6 is blocked, while the conduit #5 is open to the reservoir through the groove I46 of the valve means RV, conduit #5, groove I44 and axial passage of the valve means SV and return conduit #9, thereby permitting the discharge of fluidfrom the right end of-the bore 30 when the valve I06 is being urged to forward position by the spring I09. The communication of the conduit #5 with the reservoir 20 presupposes valve I4I of 1 v the start valve means SV in normal position, for in shifted position the groove I44 is is' blocked, thereby causing a building up of presexternal port 3 of the device II communicating with the slow feed valve 85 to control the position thereof. Groove I50 is connected to an external conduit #6 which is a branch of the control fluid supply conduit #6. It will be apparent from the foregoing that with the valve of the slow feed valve means FIV in normal position conduit #3 is open to the reservoir through the groove I 40 and the axial passage in the valve proper, thereby permitting the slow feed valve 85 to be shifted to its normal position by the spring 66 with the result that no fluid pressure is supplied through conduit #4 to shift the piston 4| of the displacement varying means. When the valve is in shifted position, however, control fluid is supplied to the port 3 through conduit #6, groove I5I and conduit #3 with the result that valve 85 is shifted and high pressure fluid isapplied to the piston M for shifting the same inwardly to reduce the displacement of the variable delivery pump I4 to a minimum. a

The last ofthe valve means F2V.is identical with the slow feed valve means and, accordingly, the casing is formed with narrow axially spaced grooves I52 and I53 opening to the bore, while the valve proper is formedat its lower end with a wide annular groove I54 and a narrow annular groove spaced upwardly from the wide groove and communicating by means of radial ports with an axial passage opening through the lower end of the valve to'the bore in the casing. Here again in normal position, the'narrow annublocked, as previously described. In shifted position, groove I48 of the reversing valve means bridges the grooves I46 and I", thereby causing the supply of control fluidto the bore 90 of the reversing valve means for shifting the valve I06 to its retum position,.valve SV being in its.

shifted position.

The casing of valve means FIV is formed with narrow, axially spaced grooves I48 and I50 opening to the bore therein, while the valve proper is formed with a wide annular groove I5I near its lower endand spaced upwardly therefrom lar groove of the valve registers with the groove I52 of the casing, while in shifted position the wide'annular groove I54 of the valve bridges grooves I52 and I53 to-eflect communication therebetween. In this instance, the groove I52 is connected by an external conduit #1 to the port 52 of the displacement varying means, while groove I53 is connected by an external conduit #8' to to the high pressure fluid supply passage 40. It will be seen that in the normal position of the intermediate feed valve means conduit #1 is open to the reservoir, while in shifted position conduit #1 is connected by means of conduit #0 to the fluid supply passage 40 thereby causing a discharge of high pressure fluid through the port 52 for acting upon the piston '49 which is then shifted inwardly to the extent permitted by the adjustable rod 50 for setting the displacement of the pump I4 at some intermediate value.-

, The hydraulic circuit is completed by the conduits leading from the device II to the motor I0. l

. rocable a piston I6I connected by a rod I62 to the table 9. The head end of the cylinder I is with a narrowgroove communicating by means v 1 l of radial ports with an axial passage opening through the lower end of the valve to -thebore in the casing. In the normal position of the I50 to effect communication therebetween. Since,

connected by a conduit I63 to'the external port 99, while the rod end of the cylinder is connected by a conduit I64 to the external port I00 of the device II. I

While the remote control valve means may be shifted by a variety of means, and while a variety of cycles of movement of the table 9 may be obtained by. a different sequence in the actuation of the valve means, or by a variation in the duration of actuation, or by the total omission of one or more of the valve means, they are herein shown as actuated electrically in a man-. I nor to obtain a cycle of operation including rapid approach, fast feed, intermediate feed, slow feed,

I rapid return and stop. Accordingly, each of the the valve means FIV is intended to control the valve means is provided witha coil I66 operable upon energization to move the valve IM to shifted" position against-the opposition of the spring switch.

I42. One end of each of the coils I66 is connected to a line wire LI, while the remaining ends of the coils I66 are adapted to be connected through mzanual or dog actuated switches to a line wire L Herein, the remaining end of the coil I66 of the start and stop valve means SV is connected to the line wire LI- through a dog actuated stop switch SS, biased to closed position, and a manual push button switch SS, biased to open position, connected in parallel with the dog actuated The coil of the reversing valve means RV is likewise connected to the line wire L2 through a dog actuated switch RS, biased to open position, and a manual push. button switch RS also biased to open position and connected in parallel with the dog actuated. switch RS. The coils of the valve means TV, FIV and F2V are termediate feed, slow feed, rapid return and stop. Accordingly, the table 9' carries a stop dog .SD, a reversing dog RD, a traverse dog I'D, a slow feed dog FID, and an intermediate feeddog F2D disposed to control the corresponding switches and positioned and shaped to cause the energization on deenergization of the coils I66 of the respective valve means at the proper time and for the proper duration to obtain the various movements in the proper sequence and for the proper length of time.

connected to .the line wire L2, respectively, by

duit and hence spring II maintains the charging I termined by the length of the traverse dog TD, the switch TS will beopened with the result that I the coil of the traverse valve means TV will be deenergized and the valve thereof returned to normal position. In this position, conduit #2 is connected to the reservoir 26 through'the conduit #9 with the result that the charging and rate change valve 16 is now urged to closed position only by the spring I I. Under that condition, the valve 16 serves merely to charge the feed pump I4, that is, the valve I6 maintains a pressure in the passage 25 and the chargingpassage 39 which is suflicient to open the intake check valves 31 of the pump I4 and impart a return stroke only to the pistons 3| thereof. The pressure of the fluid in the passage 25, however, is

not high enough to open the exhaust check valves 38 against the pressure in the passage 46 so that the feed pump functions to meter the quantity of fluid discharged to the'passage 46 and also to raise the pressure thereof; The displacement of the feed pump I4 is now at the maximum for With the cycle of operation mentioned, the.

stop dog SD is disposed to engage and open the switch SS controlling the start and stop valve SV when the table arrives at the end of its return movement, while the traverse dog TD, controlling the traverse switch TS, in the stop posi-' tion of the table shown, engages the switch to close and to maintain the same closed during the extent of movement of the table in a for- ,ward direction during which rapid traverse is desired.

The operation of the various valves and the flow of fluid through the circuit is best understood from the followingbrief description of the operation. Let it be assumed that the table is in its stop position shown and that dog SD has opened switch SS and dog TD has closed switch TS. To initiate movement of the table, the operator depresses the push button switch SS, thereby energizing the coil I66 of the start valve .means SV, with the result that the conduit #I is now blocked causing fluid pressure to build up within the start valve 6|, whereby the spring.

63'positively maintains the same closed to initi-.

ate discharge of fluid from the device II to the motor I6. The push button switch SS is held closed by the operator until the dog SD has released the switch SS and permitted the same to close. It will be apparent-that the switch SS is maintained closed "throughout the cycle of movement oi the table, thereby maintaining the valve- Ill of the start valve-means in shifted position to maintain the conduit #I blocked and.

start-valve 6| positively closed throughout the cycle of movement of the table.

It has been presupposed that the traverse switch TS would be closed by the traverse dog TD with the result that valve means VT is shifted to block the conduit #2. As a result, pressure is built up in that conwhich it has been preset by rotation of the ring 43, with the result that table Bis now driven at a fast feed rate in a forward direction. Any excess of fluid supplied by the traverse pump over that metered by the feed pump I4 is discharged to the reservoir 26 through the groove 51, passage 56 and return pipe 66.

a Fast feed movement of the table 9 continues until the intermediate feed dog FZD engages and closes the intermediate feed switch F2S. When this switch is closed, the valve of the intermediate feed valve means FZV is shifted with .the result that high pressure fluid issupplied to the port 52 of the displacement varying .means throughthe conduit #B-and the conduit #1. This causes the piston 49 tob'e shifted inwardly and imparts a corresponding movement to the piston 41 to change the displacement, of. the pump I4. The extent of movement is limited and adjusted to'provide some intermediate 'displacecausing the slow feed valve means FIV to be shifted out of normal position. With the slow I feed valve means in shifted position, conduit #3 the valve of the traverse is'connected to the control fluid supply conduit #6, with the result that theyslow feed valve is shifted to connect port 86 and groove I6. High pressure fluid from the passage 46 is then supplied through the conduit. #4 to the port 53. of

the displacement varying ineanscausing the pis-' ton 4| to be shifted inwardly to the full extent permitted by the previous adjustment of' the cam ring 44 with the-result that the displacement of the pump I4 is reduced to a minimum and the table His now moved ata slow feed rate of movement. I At the end. of the slow feed rate of movement of the table 9, the reversing dog RD engages and closes the reversing switch RS thereby causing the valve I ,of the reversing valve means RV to be shifted. This causes grooves I40 and I41 01' the reversing valve means to be bridged by the groove I48 of the valve I with the result that control fluid is now supplied through the conduit #6 and conduit #5 to the right end of the bore 90 of the reversing valve means, thereby shifting the reversing valve I06 to the left to its "return position. In its return" position, valve I uncovers the groove I03 so that. pressure fluid is-supplied to the bore 90 through the groove I03 and the duct I04 to hold the valve in freturn position even though the reversing valve means RV is only temporarily shifted. Escape of fluid out ofthe conduit #5 is prevented because the groove I44 of the start and stop valve means SV is blocked.

With the valve I06 shifted to return position,

- groove. 95 is now incommunication with groove 90 while groove 94 is'in communication with groove 93 so that pressure-fluid is .now supplied to the rod end of the cylinder I00, while fluid from. the head-end is discharged through the conduit I63,grooves 94 and 93, passages IM and I02 tothe' valve II8. In return position, valve I00 also blocks groove I05 thereby causing pressure to build up in the duct 12" and hence spring 'lI maintains the valve'I0 in closed position regardless of the position of the traverse valve TV. As a result, the entire discharge of the traverse pump I 3 is now supp ied to the motor, thereby driving the tableat a traverse rate in a return direction.

When the table returns to stop position, the stop dog SD engages, the switch SS which has been closed during theentire cycle-to open'the same and deenergize thecoil I65 of the start and stop valve means SV. The va1ve"-.I4I of the start and stop valve means SV is then returned t9 normal position by the spring'l42 connecting both grooves I43 and I44 to the reservoir. The

" of the stationary contacts of the switch RS. A third terminal of the relay is connected by a lead.

result is that the pressurefluid in the conduit #I is relieved th'ereby' placing the start valve SI solely under the control of spring 63 which then maintains a pressure insumcient to open .the intake'check valves 31 of the feed pump I4 so that no fluid is discharged to the motor and the table is brought to rest. The fluid in the rightend of the bore 90 of the reversing valve means also is free to discharge to the reservoir so that spring I08 new functions to return-the reversing valve I00 to its forward position. The fact that during the return movement of the table the traverse dog TD engaged and closed the switch TS is immaterial because" the duct' I2"- already was blocked by the valve'l06 and additional blocking of the conduit #2 by the traverse valve means causes no change in the operation. By manual closure of the push button switch RS, the table may be reversed. at traverse rate at any time dur-' ing the cycle.

Regardless of the direction of movement of the table 9, the return fluid from the motor I0 is directed by the passage I02 to the bore IIII where its return to the reservoir is controlled by the valve I I8. This valve, as previouslystated, is not responsive to the pressure of the return fluid, but is responsive solely to the pressure of the supply fluid in order that it may function to prevent overrunning of the table during a climb out or when the tool breaks through the work. Preferably', the spring I2I is so adjusted that. the valve I I8'is opened to permit substantially unrestricted 75v discharge whenthe pressure of the supply fluid. is equal to or in excess of that required to move, the table at a traverse rate and under no load.

This pressure is always less than the pressure required to move the table at a traverse rate and under no load, which pressure is always less than the pressure required to move the table during anormal cut of the tool and thus during traverse movement of the table in either direction and during a normal feed movement the valve I I8 is open permitting substantially unrestricted discharge from the passage I02 through the passage I I2 to the passage 50 and then out through the return pipe 60. During a climb cut, however,.when the tool tends to advance the table at a rate faster than that which is determined by the discharge of fluidby the pump I4, the supply pressure drops below the predetermined value for which the valve H8 is set,thereby permitting the valve to close or at least restrict the flow of return fluid -With this character of remote control means, it

is possible to obtain a dwell of the table prior to reversal without addition of further valve means or without' modification of the present valve means simply by the incorporation of a definite time relay-TR in the control of the reversing valve means RV. A fragmentary portion of the electrical control means including 'the definite time relay TR. is shown in Fig. 3. The relay is of well known construction and is connected by a lead I10 to the line wire LI and by a lead III to one "2 to one end of the coil I66 of the valve means while the other end of the coil is connected to the line wire .LI. The relay functions upon closure of the switch RS to delay the energlzation of the coil I65 a predetermined length of time. As a result, whenthe reversing dog RD engages the reversing switch RS and closes the same, the valve I4I of the reversing valve means RV is not immediately shifted but is delayed during the desired dwell period. When the time relay is employed,a conventional positive stop, not shown, 'is'also provided with which the table 9 abuts at the beginning of the dwell period. f

It is believed apparent from the foregoing that I have provided a unique form of remote control means which provides an unusually flexible control because each valve means is independent in its operation, in its control, and in its construction. This enables any desired number of valve means to be employed and permits each to be actuated at a predetermined point in themovement of the table and for a predetermined length I of time simply by the proper location of a dog of suitable length. By controlling the valves electrically they may be mounted on the machine tool adjacent the pressure generating and control device and need not be mounted inmiediately adjacent the table.

I claim as my invention: 1. In combination with a member to be driven, a hydraulic actuator system for driving the same comprising a motor, pumping mechanism operable to discharge fluid under pressure to said motor and governing mechanism associated with said pumping mechanism to determine the direction and volume of fluid discharge therefrom, electrically actuated remote control means hydraulically connected with the governing mechanism to control the same including a normally open manual switch operable upon' closure to initiate the discharge of fluid from the pumping mechanism to impart movement to the member, a normally closed dog actuated switch, a dog for holding said switch open when the member is in its stop position, said dog being withdrawn and said ,nected with the governing mechanism to control charge from the pumping mechanism to *efiect a reversal in the direction of movement of the member.

2. In a hydraulic actuator for driving a member at different rates of movement and in opposite directions, in combination, a reservoir, a hydraulic motor operatively associated with the member for driving the same, pumping mechanism operable to draw fluid from the reservoir and to discharge the same under pressure to the motor, governing mechanism associated with said pumping mechanism for determining the direction and volume of fluid discharge by the pumping mechanism to the motor including a hydraulically controlled start and stop valve, a hydraulically controlled rate change valve, and a reversing valve biased to forward position adapted to be hydraulically shifted to return position, and remote control means comprising a start and stop valve means hydraulically.

connected-to the start and stop valve of the governing mechanism to control the same, a traverse valve means hydraulically associated with the rate change valve of the governing mechanism to control that valve, a reversing valve means hythe same, including a normally open manual switch operable upon closure to initiate discharge of fluid from the pumping mechanism to impart movement to the member, a first dog actuated switch controlling said rate valve and operable while closed during movement of the member to cause a particular rate of movement of the member and operable when open to'cause said pumping mechanism to discharge at a different rate, and a second normally open dog actuated switch closed at the end of movement of the member in the first direction-and operable upon closure to effect a reversal in the direction of fluid discharge from the pumping mechanism to efiect reversal in the direction of movement of the member.

4. In combinationwith a member to be driven,

a hydraulic actuator system for driving the same comprising, in combination, a 'motor, pumping mechanism operable to discharge fluid under pressure to said motor, governing mechanism associated with said pumping mechanism to determine the volume of fluid discharge therefrom, and electrically actuated remote control means hydraulically connected with the governing mechanism to control the same including a normally open manual switch operable upon closure to initiate discharge of fluid from the mechanism to impart movement to the member, a first dog actu ated switch operable while closed during movement of the member to cause a traverse rate of movement of the member, and a second dog actuill draulically associated with the reversing valve of the goveming mechanism to efiect shift thereof to return position, and electrical control means for actuating said remote control valve means comprising a solenoid for each of said valve means, a dog actuated switch'biased to, closed position and a push button switch biased to open position connected in parallel with said dog actuated switch for controlling the energization of the solenoid of the start and stop valve means, a dog actuated switch biased to open position and a push button switch biased to open position connected in parallelwith said last named dog actuated switch for controlling the energization of thesolenoid of said reversing valve means, and

- a third dog actuated switch biased to open posi s aid' traverse valve means.

8. In combination with a member to be driven,

tion and connected in series with the solenoid of a hydraulic actuator system for driving the same comprising, in combination, a motor, pumping mechanism operable to discharge fluid upder pressure and at diflerentvolumes to said motor, gov erning mechanism associated with said pumping mechanism to determine the direction and volume of fluid discharge therefrom including a valve for controlling the rate of fluid discharge from said pumpingmechanism, and'electrlcally actuated remotecontrol means hydraulically conated switch operable upon closure, and when said first dog actuated switch is open,-to cause a feed rate of movement of the member.

5. In combination with a member to be driven, a hydraulic actuator system for driving the same comprising, in combination, a motor, pumping mechanism, including a variable displacement pump having a hydraulically actuated volume changing device, operable to discharge fluid under pressure and at different volumes to said motor, valve mechanism associated with said pumping mechanism to determine the direction and volume of fluid discharge therefrom, and electrically actuated remote control means hydraulically connected with said valve mechanism to control the same including a valve governing the supply of fluid to said volume changing device, a normally open manual switch operable upon closure to initiate discharge of fluid from the pumping mechanism to impart movement to the member, a dog actuated switch operable while closed during movement of the member to cause a traverse rate of movement of the member, a second dog actuated switch governing said valve and operable upon closure to cause fluid to be supplied to said volume changing device, and a third dog actuated switch closed at the end of movement of the member in the first direction and operable upon closure to efiect a reversal in the direction of fluid discharge from the pumping mechanism-to efiect reversal in the direction of movement of the member. v

6. Ina hydraulic actuator system for driving a member at different rates of movement and in opposite directions, in combination, a hydraulic motor operatiyely associated with the member for driving the same, pumping mechanism operable I to discharge fluid under pressure to the motor,

governing mechanism associated with said pump-' ing mechanismfor determining the direction and 1'0 trolled rate change valve, and a reversing valve adapted to be hydraulically shifted from a forward to a return position, remote control means comprising a start and stop valve means, hydraulically connected to the startand stop valve of the governing mechanism to control the same,

a traverse valve means hydraulically associated with themate change valve of the governing mechanism to control that valve, areversing valve means hydraulically associated with the reversing valve of the governing mechansm to efcontrol meansfor actuating said remote control valve means comprising a solenoid for each of said valve means, a push button switch biased'to open position for controlling the energization of the solenoid of the start and stop valve means, a dogfeet shift thereof to return position, and electrical actuated switchbiased to open position for controlling the energization of the solenoid of said reversing valve means, and a dog actuated switch biased to open position-for controlling the energization of the solenoid of said traverse valve means.

7. In a hydraulic actuator, system for driving a member at diiierent rates oilmovement and in opposite directions, in combination, a hydraulic motor operatively associated with the member for driving the same, pumpingmechanlsm operable to discharge fluid under pressure to the motor, 7 governing mechanism associated with said pumping mechanism for determining the direction and volume of fluid discharge by the pumping mechanism to the motor including a hydraulically controlled start and-stop valve, 9, hydraulically controlled rate change valve, and a reversing valve adapted to be hydraulically shifted from a forward to a'return position, remotecontrol means comprising a start andstop valve means hydraulicaily connected to the start and stop valve of the governing mechanism to control the same,'a traverse valve-means hydraulically associated with the rate change valve of the governing mechanism to control that --valve, a reversing valve means hydraulically associated with the reversing valve of the governing mec to eflect shift thereof 2,257,140 g I motor operatively' associated with the member for driving the sauna-pumping mechanism operable .to discharge fluid under pressure to the motor,

governing mechanism associated with said pumping mechanism for determining the direction and volume of fluid discharge by the pumping mechanism to the motor including a hydraulically controlled start and stop valve, 9. hydraulicallyv con- 5 trolled rate change valve, and'a reversing valve adapted to be hydraulically shifted from a forward to a return position, remote control means comprising a start and stop valve means hydraulically connected to the start and stop valve of the governing mechanismto control the same, a

rate change valvemeans hydraulically associated with the rate change'valve of the governingmechanism to control that valve, a reversing valve means hydraulically emsociated with the reversing .valvaoi ,the governing mechanism to efiect shift thereof to return position;- and electrical control 'means for actuating said remote control valve means comprising a solenoid for each of said valve means, a first dog actuated switch for controlling the'deenergization of the solenoid of the start and stop valve means, a second dog actuated switch for controlling the energization of.

the solenoid of said reversing valve means, and a third dog. actuated switch for controlling the energization of the wlenoid of said traverse valve means.

9.-In a hydrauiic actuator system for driving I mining the direction and volume ,of fluid suppliedby the pumping mechanism to the motor ilicomprising a first valve operable to efiect the initiation and arrest .of fluid supplied to the motor,

a second valve operable to condition the pumping I mechanism to discharge fluid to the motor at a 1 rate causing a traversemovement-oi the memto return position, and electrical control means for actuating said remote control valve means comprising a solenoid for each-of said valve means, a dog actuated switch biased. to closed-position for, controlling the energization of the solenoid of the start and stop valve means, a dog actuated switch biased to open position for con- 8.- In a hydraulic actuator for driving 5 a member at diiferent rates of movement and in opposite directions, incombination, a hydraulic f trolling the energization of the solenoid of said j reversing valve means, and a third dog actuated 1 switch biased-to open position for controlling-the energization of the solenoid of said traverse valve means.

her, a third valve governing the direction of flow or fluid from the pumping mechanism to the motor when the pumping mechanism is supplying fluid to the motor, and a iourth valve'operable to condition the pumping mechanism to supply fluid to the motor causing a feed movement of the member when said second valve is inoperative to obtain a traverse -movementoi the member,

and a plurality of individually operable two-position remote controlvalves, each connected in controlling relation with one of said first mentioned valves and each spring biased to one-oi its two positions, each of said remote control valves when moved to the other of its positions effecting the operation of the valve with which it is connected.

GUNNAR A. W 

